The "standard" width for blanks is ¾" X ¾". Since you are selecting the size, you can change that...up or down. For example, a straight profile slimline from an easy-to-drill material, could be made from a blank barely ½" X ½". That sizing would yield more pens from a given plank. But if you go for it, then find that a large number blow out during drilling, then very thin blanks would be the poor choice. You specify Jr. Gent II, which can be turned from blanks slightly less than ¾", and the blank length can be only what is needed, somewhat less than 5". So if you are going to squeeze out more blanks by downsizing, test and be sure it works before cutting up the entire board!